Process and apparatus for treating petroleum hydrocarbons



PROCESS AND APPARATUS FOR TREATING PETROLEUM HYDROCARBONS Filed Feb. 27, 1926 sb/esa;

AT ORNEY.

atente Apr. 14, 1931 UNITED STATES anniV PATENT oFFicE 'WALTER M. CROSS, OF KANSAS CITY, MISSOURI, ASSIGNOR, BY MESNE ASSIGNMENTS,

TO GASOLINE PRODUCTS COMPANY, WILMINGTON, DELAWARE, A CORPORA- TION Ol' DELAWARE PROCESS AND AIPABATUS FOR TREATING PETROLEUM HYDROCARIBONS Application led February 27, 1926. Serial No. 91,246.,

This invention relates to improvements in a process and apparatus for treating petroleum hydrocarbons, land refers more particularly to a process in which the oil is preliminarily decomposed or cracked in an apparatus in which the conversion takes place while the oil is maintained under a pressure sucient to prevent substantial distillation, and in the utilization of a steam still or other 1@ heating means in connection with the aforesaid apparatus by means of which the unvaporized oil, or what is termed as the liquid residue, is kept in a highly heated condition and in this state is utilized as a` burning'oil is or fuel oil for this apparatus or for heating other apparatuses in the immediate or near vicinity.

Among the objects of the invention are to rovide a process in which the oil, after beao ing cracked in substantially the liquid phase, is passed to a stage wherein the pressure is reduced resulting in the evolution of vapors which are subjected to a reiiuxing action and thence to a final condensing action while the at unvaporized material accumulated in the vaporizing stage of reduced pressure 1s drawny od and directed to a separate still where it is redistilled to recover therefrom any additional light fractions contained therein,`while the fuel oil bottom while 1n a highly heated state is piped for burning to nearby furnaces. A further object of the in` vention is the combining in a single apparatus of means for extracting the lighter fractions from the oil and vthe furnishing of a separate circulate system for the economical disposition o the fuel oil bottom recovered from the vaporizing stage.

The single igure is a diagrammatic side elevational viewof the apparatus with parts shown in section and parts broken away.`

ferring to the drawings at 1 is shown a stock tank. 2 is a furnace in which is positioned a coil 3. The furnace is preferably heated by means of oil burners diagrammaticall shown at 4. A reaction chamber 5 is pre erably fabricated by forging a single ingot of steel to produce a chamber having bottle necked open ends, which are closed by 5o me of removable plates 6, bolted to the i flanged ends of the chamber and facilitating the cleaning of the chamber. This chamber is preferably heavily insulated to prevent loss of heat by radiation. This chamber is connected by means of a transfer line 7 in which is interposed a valve 8 to an evaporator or vaporizer 9. The vaporizer communicates through a vapor line 10 with the refluxing tower or de hlegmator 11. This refluXing tower is pre erably of the bubble type, although a battle tower ma be used in its place, the latter beingless e ective in its operation. An overhead line 12 connects the refluxing towers with a spiral coil 13 positioned in the water cooled condenser box 14. The discharge end of this coil terminates in a line 15 which connects to the gas separator 16, the latter being equipped with a liquid draw off line 17 controlled b v a valve 18 and a gas relief line 19 regulated by a valve 20.

At 21 is shown a steam still heated by means of a steam coil 22 positioned internally thereof and supplied by steam from any suitable source, not shown. Instead of a steam still, the still 21 may be externally fired, although in the heating of heavy residual material the internal steam coil has proved somewhat more satisfactory. The still 21 is connected 'to the draw od line 23 of the vaporizer 9.

The dome of the steam still has a vapor line 24 connected to the spiral coil 25 in the water cooled condenser 26. The discharge'- from the condenser coil is a line 27 which is connected to the suction side of the pump 28; thus providing a means for recycling the overhead distillate from the steam still back to the heating coil 3 through the line 29.

Tn operation a cracking stock is supplied to the system from the tank 1 through the pipe 30 through a heating exchanger coil 32 positioned in the top of the tower 11. After preheating the oil is directed tothe line 33 and pipe 34: to the heating coil 3 in the furnace 2. It is circulated through this coil 3 at a high velocity and is therein heated to a cracking temperature. The heating and velocity of circulation are so regulated as to prevent the deposition and accumulation of ree carbon which is separated from the oil during the cracking thereof. The oil is discharged from the coil through the transfer linev 35 .into the reaction chamber 5 where it is accumulated'in a considerable body and is given suicient time to consummate the cracking which was initiated in the heating coil. The temperature and pressure conditions in the coil 3 and the chamber 5 are substantially the same, and are regulated to effect relatively lcomplete conversion of the particular oil undergoing treatment. It is obvious, of course, that the temperature in the coil will be somewhat in excess of the temperature in the chamber due to loss of heat by radiation, but this is prevented insofar as is possible. The pressure maintained upon this part of the apparatus is regulated to prevent any substantial distillation of the oil and to effect the cracking of the oil while the same is maintained substantially in the liquid phase. @n discharge from the reaction chamber the oil passes through the line 7, the pressure being released at the valve 8. With this release of pressure there is a consequential evolution of vapors which constitute the lighter or lower boiling point fractions. It may be necessary at this point to introduce a cooler hydrocarbon medium or steam in order to prevent excessive vaporization and the reduction of the petroleum hydrocarbons completely to the vapor phase and a residual coke. Temperature conditions at this point are controlled to produce vaporization of the oil fractions constituting the lighter ends, such as naphtha, kerosene, and a rather deep cut into the gas oil fractions. rl`hese materials pass overhead through the lines l0,

and are introduced into the bottom of the. tower 11.

The unvaporized liquid constituting a fuel oil bottom is drawn ofi' from the lower part of the vaporizer 9 through the line 23 by means of a valve 36 which may be manually controlled or automatically controlled by a liquid level control device manipulated by a float regulated by the liquid level in the evaporator. This fuel oil bottom is passed through the line 23 to the still 2l where additional heat is supplied thereto, sufficient to drive o any remaining light fractions which pass overhead from the still through the line 24 to a final condenser coil 25. The distillate recovered therefrom being recycled, as previously mentioned to the system for retreatment.

The heated fuel oil accumulation in the still 21 is withdrawn therefrom through a pipe 37, in which is interposed the'valve 38, and is circulated by means of the hot oil pump 39 through a pipe line 40 which should be heavily insulated to prevent chilling of the fuel oil during its circulation to nearby apparatus Where the oilY is to be used as fuel. In the drawing a single line 40 with a return line 41 is shown for the circulation of the fuel oil, and secondary lines 42 having connections with the burners 4 show the manner in which the fuel oil may be tapped from the circulating main. It is understood that `a net work of connecting insulated pipes may be laid throughoutthe plant, and the fuel oil tapped olf from these mains at any desired location to be used as a burning oil in other furnaces or apparatus than the particular system in which it was produced. The return vline serves to return any excess oil to the still 21 in order that its temperature shall be 'kept up and the oil maintained in a free flowing condition.

The vapors passing over from the evaporating tower to the bubble tower ll are therein subjected to a refluxing action and the higher boiling point fractions separated out and flowing by gravity to the bottom of the tower where they are drawn 0E though the pipe 43 and either recycled to the heating coil for retreatment in the system or diverted from the system through the line 44 regulated by valve 45.

To supplement the use of the fuel oil which is circulated back to the furnace in the manner described the gas drawn od from the top of the gas separator through the line 19 may be also used as a combustion medium, either in the furnace 2 or in other apparatuses in the plant. With proper treatment this gas is adaptable to domestic use, as well as for commercial purposes other than in the furnace here shown.

In case the still 21 is incapable of handling all of the fuel oil produced, a line 46 controlled by a valve 47 is connected into the draw-off line 23 in order that excess oil may be diverted from the system or the fuel oil bottom diverted from the still 2l to an alternate still or to storage in case it becomes necessary to clean out the steam still 21.

It is recognized as common practice to direct lthe fuel oil withdrawn from the vaporizing stage of a cracking system to storage and thereafter draw the oil from storage and pump it to the points desired for consumption as fuel. Such practice is attended by certain disadvantages primarily due to the character of this fuel oil bottom as it has a tendency upon cooling to become a viscous,

non-flowing oil from which separates heavy polymers, or free carbonaceous material which is extremely objectionable when accumulated in a storage tank. By means of the present practice these objectionable features have been eliminated as the oil is kept in a hot free flowing state, in Vwhich condi- .tion it is at all times available and adaptable for burning purposes.

A check valve 48 is interposed in the line 23 through which the residual fuel oil is directed to the steam still to prevent the backing up of the oil by pressure accumulating in the still 21.

I claim as my invention -A 1. An apparatus for the conversion of hydrocarbon oils, comprising a heating stage, a cracking stage, and an evaporating stage serially connected, a separate still connected to receive unvaporized oil from the evaporating stage, a fuel supply line for the heating stage connected to the still adapted to burn residuum from the evaporating stage, said still, and fuel supply line being connected in a closed cycle, a vapor drawoi line from the still and means connected with the line to condense the vapors and return the condensate to the heating stage for retreatment.

2. A process for converting hydrocarbon oil, comprising the steps of heating the oil to cracking temperature in a heating stage, passing the oil out to a separate stage wherein cracking is consummated, vaporizing the lighter fractions of the cracked product in an evaporating stage, directing the unvaporized material from the evaporating stage to a separate distilling stage wherein additions overhead fractions are removed, coursing the residual oil from the distilling stage to the burners of the heating stage in a closed cycle, and condensing the said removed fractions from said distilling stage and returning them to the heating stage for retreatment therein.

3. A process for the conversion of hydrocarbon oil, comprising heating the oil in a heating stage, passing the oil therefrom to a conversion stage wherein temperature and pressure conditions are maintained to permit cracking without substantial distillation, conducting the oil to an evaporating stage wherein a portion of the cracked product is distilled, removing the residual oil from the evaporating stage and passing it to a separate still wherein distillation of lighter fractions occurs, passing the residual Huid from the still to the burners of the heating stage and back to said still in a closed cycle, continuously withdrawing cycled stock for fuel, withdrawing and condensing the distilled lighter fractions from said separate still and returning them throughout the heating stage for retreatment.

WALTER M. CROSS.

oERTirieATE or eomieeiioei.

Patent No. 1,800,436. GranteApril 14, 193i, to

WALTER M. moss.

it is hereby eertied ther error appears in the printed specification of the ahove numbered paeni requiring correction as follows: Page 3, line 7, claim l, for the words "evaporating stage" read siili, and lines 22 and 23, claim 2, for "additions" read additional; and that the seid Letters Paten should be read with these corrections therein that the some may conform to the record of the case in the Patent @ffice Signed and sealed this 12th day of Aprii, A. D. 1932,

y y r l M. J. Moore, (Seal) Acting Commissioner of Patents. 

